#include "utils.h"
#include "unittest.h"

#include <fstream>
#include <cassert>

static const std::string dirSep = "/";

static int CRC32Table[256] =
{
	0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
	0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
	0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
	0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
	0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
	0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
	0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
	0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
	0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
	0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
	0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
	0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
	0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
	0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
	0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
	0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,

	0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
	0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
	0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
	0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
	0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
	0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
	0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
	0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
	0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
	0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
	0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
	0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
	0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
	0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
	0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
	0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,

	0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
	0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
	0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
	0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
	0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
	0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
	0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
	0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
	0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
	0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
	0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
	0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
	0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
	0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
	0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
	0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,

	0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
	0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
	0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
	0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
	0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
	0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
	0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
	0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
	0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
	0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
	0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
	0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
	0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
	0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
	0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
	0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
};

void getCRC32(const char byte, int &dwCRC32)
{
	dwCRC32 = (( dwCRC32 ) >> 8 ) ^ CRC32Table[( byte ) ^ (( dwCRC32 ) & 0x000000FF )];
}

int getCrc32(const std::string & file)
{
	int crc = 0xFFFFFFFF;
	
	std::ifstream f(file.c_str(), std::ios_base::binary);
	while (f)
	{
		char byte = f.get();
		getCRC32(byte, crc);
	}
	
	crc = ~crc;
	return crc;
}

std::string implode(const std::vector <std::string> & toImplode, const std::string & sep)
{
	std::string out;
	
	for (std::vector <std::string>::const_iterator i = toImplode.begin(); i != toImplode.end(); i++)
	{
		if (i != toImplode.begin())
			out.append(sep);
		out.append(*i);
	}
	
	return out;
}

std::vector <std::string> explode(const std::string & toExplode, const std::string & sep)
{
	std::vector <std::string> out;
	size_t lastPos = 0;
	size_t curPos = 0;
	
	curPos = toExplode.find(sep, lastPos);
	while (curPos != std::string::npos)
	{
		out.push_back(toExplode.substr(lastPos, curPos-lastPos));
		lastPos = curPos+sep.size();
		curPos = toExplode.find(sep, lastPos);
	}
	
	if (lastPos != curPos && lastPos < toExplode.size())
		out.push_back(toExplode.substr(lastPos));
	else
		out.push_back("");
	
	return out;
}

bool pathIsAbsolute(const std::string & pathString)
{
	std::vector <std::string> path = explode(pathString, dirSep);
	if (!path.empty() && (path.front().empty() || (path.front().size() == 2 && path.front()[1] == ':')))
		return true;
	else
		return false;
}

// edits path in place
void systemToFileDirSep(std::string & path)
{
	#ifdef WIN32
	for (int i = 0; i < path.size(); i++)
	{
		if (path[i] == '\\')
			path[i] = '/';
	}
	#endif
}

std::string makeRelativePath(const std::string & absoluteReferencePoint, const std::string & absolutePath)
{
	std::vector <std::string> reference = explode(absoluteReferencePoint, dirSep);
	if (!reference.empty()) reference.pop_back();
	std::vector <std::string> path = explode(absolutePath, dirSep);
	std::vector <std::string> relative;
	
	// ensure these are really absolute paths
	if (!pathIsAbsolute(absoluteReferencePoint))
	{
		std::cerr << absoluteReferencePoint << std::endl;
		assert(pathIsAbsolute(absoluteReferencePoint));
	}
	if (!pathIsAbsolute(absolutePath))
		return absolutePath;
	
	// find index of shared path
	int sharedIdx = 0;
	for (int i = 0; i < reference.size() && i < path.size(); i++)
	{
		if (reference[i] != path[i])
			break;
		
		sharedIdx = i;
	}
	
	// insert .. elements
	int backElements = reference.size() - sharedIdx - 1;
	for (int i = 0; i < backElements; i++)
		relative.push_back("..");
	
	// insert remaining path
	for (int i = sharedIdx+1; i < path.size(); i++)
	{
		relative.push_back(path[i]);
	}
	
	return implode(relative, dirSep);
}

std::string makeAbsolutePath(const std::string & absoluteReferencePoint, const std::string & relativePath)
{
	std::vector <std::string> reference = explode(absoluteReferencePoint, dirSep);
	if (!reference.empty()) reference.pop_back();
	std::vector <std::string> path = explode(relativePath, dirSep);
	std::vector <std::string> absolute;
	
	// if the relative path is actually absolute, then we don't have to do anything
	if (pathIsAbsolute(relativePath))
		return relativePath;
	
	// ensure this is really an absolute path
	if (!pathIsAbsolute(absoluteReferencePoint))
	{
		std::cerr << absoluteReferencePoint << std::endl;
		assert(pathIsAbsolute(absoluteReferencePoint));
	}
	
	// count .. elements
	int backElements = 0;
	for (int i = 0; i < path.size(); i++)
	{
		if (path[i] == "..")
			backElements++;
		else
			break;
	}
	
	// append first (shared) part of path
	assert(reference.size()-backElements >= 0);
	for (int i = 0; i < reference.size() - backElements; i++)
	{
		absolute.push_back(reference[i]);
	}
	
	// append non-shared part of path
	for (int i = backElements; i < path.size(); i++)
	{
		absolute.push_back(path[i]);
	}
	
	return implode(absolute, dirSep);
}

std::string stripPath(const std::string & filepath)
{
	std::string fixedfile = filepath;
	systemToFileDirSep(fixedfile);
	return explode(fixedfile, "/").back();
}

bool hasExtension(const std::string & path, const std::string & extension)
{
   if (extension.empty())
       return true;

   bool result = false;

   if (path.find(extension) == path.length() - extension.length())
       result = true;

   return result;
}

QT_TEST(utils_test)
{
	{
		std::vector <std::string> exploded = explode("/home/joe/code/test.hog", "/");
		QT_CHECK_EQUAL(exploded.size(), 5);
		if (exploded.size() > 0) QT_CHECK_EQUAL(exploded[0], "");
		if (exploded.size() > 1) QT_CHECK_EQUAL(exploded[1], "home");
		if (exploded.size() > 2) QT_CHECK_EQUAL(exploded[2], "joe");
		if (exploded.size() > 3) QT_CHECK_EQUAL(exploded[3], "code");
		if (exploded.size() > 4) QT_CHECK_EQUAL(exploded[4], "test.hog");
	}
	
	{
		std::vector <std::string> exploded = explode("/home/joe/code/", "/");
		QT_CHECK_EQUAL(exploded.size(), 5);
		if (exploded.size() > 0) QT_CHECK_EQUAL(exploded[0], "");
		if (exploded.size() > 1) QT_CHECK_EQUAL(exploded[1], "home");
		if (exploded.size() > 2) QT_CHECK_EQUAL(exploded[2], "joe");
		if (exploded.size() > 3) QT_CHECK_EQUAL(exploded[3], "code");
		if (exploded.size() > 4) QT_CHECK_EQUAL(exploded[4], "");
	}
	
	{
		std::vector <std::string> exploded = explode("c:/home/joe/code/test.hog", "/");
		QT_CHECK_EQUAL(exploded.size(), 5);
		if (exploded.size() > 0) QT_CHECK_EQUAL(exploded[0], "c:");
		if (exploded.size() > 1) QT_CHECK_EQUAL(exploded[1], "home");
		if (exploded.size() > 2) QT_CHECK_EQUAL(exploded[2], "joe");
		if (exploded.size() > 3) QT_CHECK_EQUAL(exploded[3], "code");
		if (exploded.size() > 4) QT_CHECK_EQUAL(exploded[4], "test.hog");
	}
	
	std::string refPath = dirSep+"home"+dirSep+"joe"+dirSep+"test.hog";
	std::string relPath1 = "data"+dirSep+"texture.png";
	std::string absPath1 = dirSep+"home"+dirSep+"joe"+dirSep+"data"+dirSep+"texture.png";
	std::string relPath2 = ".."+dirSep+"data"+dirSep+"texture.png";
	std::string absPath2 = dirSep+"home"+dirSep+"data"+dirSep+"texture.png";
	QT_CHECK_EQUAL(makeAbsolutePath(refPath, relPath1), absPath1);
	QT_CHECK_EQUAL(makeAbsolutePath(refPath, relPath2), absPath2);
	QT_CHECK_EQUAL(makeRelativePath(refPath, absPath1), relPath1);
	QT_CHECK_EQUAL(makeRelativePath(refPath, absPath2), relPath2);
	
	QT_CHECK_EQUAL(stripPath("/home/joe/test123"), "test123");
	QT_CHECK_EQUAL(stripPath("test123"), "test123");
	QT_CHECK_EQUAL(stripPath("/home/joe/test123.txt"), "test123.txt");
	QT_CHECK_EQUAL(stripPath("//test123"), "test123");
	QT_CHECK_EQUAL(stripPath("/home/joe/test123/"), "");
	QT_CHECK_EQUAL(stripPath("home/joe/test123"), "test123");

    QT_CHECK(!hasExtension("", ".pfm"));
    QT_CHECK(hasExtension(".pfm", ".pfm"));
    QT_CHECK(hasExtension("testfile.pfm", ".pfm"));
    QT_CHECK(hasExtension("", ""));
    QT_CHECK(hasExtension("testing123", ""));
}

